Study On The Screening And Application Of Watermelon Rootstock Tolerance To Waterlogging

In this experiment,11 different types watermelon rootstocks from East China were screened out,by artificially simulating the flooding environment and Comprehensive comparison.Grafting was conducted with 'Zaojia 8424' as the scion,and the self-rooted seedlings of 'Zaojia 8424' were used as the control.The influence of rootstocks on grafted watermelon seedlings,including on its photosynthetic parameters,physiological characteristics,mineral nutrient uptake,yield and quality of fruit had been researched.The results are as follows:1.In the waterlogging resistant identification of watermelon rootstock seedlings,root length,shoot dry weight,root dry weight,chlorophyll content and photosynthetic rate were reliable indicators.According to comprehensive evaluation on 11 species of rootstocks with membership function method,'Xuesong' had the highest membership function value and the best resistance against waterlogging,whereas 'Zhenwang' had the lowest membership function value and the weakest resistance against waterlogging.Pumpkin rootstock's waterlogging resistance was higher than cucurbit stock.2.Under flooding stress,the resistance of grafted watermelon seedlings were stronger than that of the control treatments.Grafting of watermelon through rootstock,not only maintained better root morphology and structure,but also significantly increased the root activity,protective enzyme activity and osmoregulatory content of grafted watermelon seedlings,thereby reducing the damage of cell membranes caused by waterlogging stress and improving the tolerance of watermelon seedlings.Grafting of watermelon through rootstock also increases the content of mineral elements such as N,P,K,Ca,Mg in seedlings.watermelon seedlings grafted with 'Xuesong' rootstock had the strongest resistance to waterlogging,followed by watermelon seedlings grafted with 'Qianggen' and 'heli' rootstocks.3.Compared with self-rooted ones,grafting not only increased watermelon fruit yield,but also increased peel thickness,as well as soluble solids,soluble sugar,lycopene and Vc content,thereby enhancing the nutritional quality of the fruit.Yields of watermelons grafted with pumpkin rootstocks remarkably increased compared to those grafted with gourd rootstocks,but the later one had better flavor in terms of quality.By means of membership function method,it was found that 'Qianggen' had the best quality as grafting rootstocks against waterlogging,followed by 'Xuesong' and'Zhenwang',while 'Heli' had worse quality than self-rooted seedlings.